1. Field of the Invention
The present invention relates to an evaporative humidifier having a wick change indicator. More particularly, the present invention relates to a wick change indicator that monitors the performance of the wick to assess whether the wick requires replacement.
2. Description of the Prior Art
Humidifiers are useful in raising the humidity of air inside homes, particularly during periods of dry weather during the winter and heat inside a home causes the relative humidity within the home to be lowered to an uncomfortable level. Under these circumstances, it is beneficial to introduce moisture into the air. Several types of humidifiers for increasing humidity in a room are well known in the art, and include steam-type, ultrasonic, warm-air and evaporative humidifiers.
Certain humidifiers, and in particular the evaporative type, generally include a housing having an inlet, an outlet, and a reservoir for holding water, a water absorbing material seated partially submerged in the water of the reservoir, and a fan that is connected to the housing for creating an airflow. The water absorbing material is generally known as a wick in the art and is adapted to draw water in the upper nonemersed part by capillary action. The airflow created by the fan is directed to pass through the upper non-emersed portion of the wick to humidify the air in the room.
A problem associated with humidifiers that utilize wicks is that they tend to accumulate minerals from the water which blocks the capillary action of the wick. Accordingly, the performance of the wick degrades over time requiring replacement.
It is difficult to determine when a wick requires replacement by physical inspection or by monitoring the period of actual use. This is because both of these methods do not assess the actual performance of the wick. The wick will change color as a result of the absorption of various minerals over a period of a time. Since the minerals that exist in public water supplies vary from one municipality to another, practical replacement guidelines based only on a physical inspection and monitoring the length of use are not practical.
Commonly assigned U.S. Pat. No. 5,800,741 to Glenn et al. discloses an evaporative humidifier having a wick filter with color change indicator The wick change indicator disclosed therein was premised upon a color change indicator that would change color after a period of use. As noted in the specification at Column 9, Lines 45-53, although the life of the wick filter is estimated to be approximately 6 weeks, the water supply can have an adverse effect on the color change indicator disclosed therein.